Under this fellowship, we propose to use information theoretic techniques to quantify the flow of information about complex acoustic stimuli through the cochlear nucleus (CN) and the central nucleus of the inferior colliculus (ICC) of decerebrate cats. These structures are obligatory stops in the auditory pathway to the cortex, and each contains several different response types that process the auditory signal in parallel. Our hypothesis is that these different response types have arisen to encode separately the various aspects of acoustic stimuli. For example, some response types may be encoding information about the temporal envelope of the acoustic pressure wave, others may be sensitive to the local spectral structure of the sound, and still others may be involved in processing the sound's location. We will test the relative sensitivity of various response types to the temporal and spectral envelopes of sound with speech-like characteristics, as well as to location cues embedded in interaural differences.